A Boeing 747 with mass 400 000 kg, engine thrust (force pushing the plane) of 1000 kN and cross section area of 158 m² is circling at constant speed of 500 km/h with the radius of 4 km at constant elevation. The acceleration of the plane and the drag force of the air is:
a) 4.8 m/s², 1000 kN
b) 62.5 m/s², 1000 kN
c) 4.8 m/s², 4 000 kN
d) 62.5 m/s², 4000 kN
e) 9.8 m/s², 1000 kN